Bug 2003511 - Cancel loading bookmarks if weve navigated from the Bookmarks Fragment

[try](https://treeherder.mozilla.org/jobs?repo=try&landoCommitID=174243)

Pull request: #34

Author: boek

mobile/android/fenix/app/src/main/java/org/mozilla/fenix/bookmarks/BookmarkFragment.kt

@@ -111,6 +111,7 @@ class BookmarkFragment : Fragment() {
                                 BookmarksSyncMiddleware(requireComponents.backgroundServices.syncStore, lifecycleScope),
                                 BrowserToolbarSyncToBookmarksMiddleware(toolbarStore, lifecycleScope),
                                 BookmarksMiddleware(
+                                    lifecycleScope = lifecycleScope,
                                     bookmarksStorage = requireContext().bookmarkStorage,
                                     clipboardManager = requireActivity().getSystemService(),
                                     addNewTabUseCase = requireComponents.useCases.tabsUseCases.addTab,

mobile/android/fenix/app/src/main/java/org/mozilla/fenix/bookmarks/BookmarksMiddleware.kt

@@ -10,6 +10,7 @@ import androidx.navigation.NavController
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ensureActive
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import mozilla.appservices.places.BookmarkRoot
@@ -51,6 +52,7 @@ private const val WARN_OPEN_ALL_SIZE = 15
  * @param reportResultGlobally Invoked when an error occurs that needs to be reported even if the
  * feature goes out of scope.
  * @param ioDispatcher Coroutine dispatcher for IO operations.
+ * @param lifecycleScope lifecycle bound CoroutineScope scope used to cancel jobs when leaving bookmarks.
  */
 @Suppress("LongParameterList", "LargeClass")
 internal class BookmarksMiddleware(
@@ -73,9 +75,10 @@ internal class BookmarksMiddleware(
     private val lastSavedFolderCache: LastSavedFolderCache,
     private val reportResultGlobally: (BookmarksGlobalResultReport) -> Unit,
     private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
+    lifecycleScope: CoroutineScope,
 ) : Middleware<BookmarksState, BookmarksAction> {
 
-    private val scope = CoroutineScope(ioDispatcher)
+    private val scope = CoroutineScope(lifecycleScope.coroutineContext + ioDispatcher)
 
     @Suppress("LongMethod", "CognitiveComplexMethod", "CyclomaticComplexMethod")
     override fun invoke(
@@ -278,6 +281,10 @@ internal class BookmarksMiddleware(
                     }
                     // list screen cases
                     preReductionState.selectedItems.isNotEmpty() -> { /* noop */ }
+                    // User is clicking back before we've loaded anything
+                    preReductionState.currentFolder.guid.isEmpty() -> {
+                        exitBookmarks()
+                    }
                     preReductionState.currentFolder.guid != BookmarkRoot.Mobile.id -> {
                         scope.launch {
                             val parentFolderGuid = withContext(ioDispatcher) {
@@ -516,6 +523,8 @@ internal class BookmarksMiddleware(
     private fun Store<BookmarksState, BookmarksAction>.tryDispatchLoadFor(guid: String) =
         scope.launch {
             bookmarksStorage.getTree(guid).getOrNull()?.let { rootNode ->
+                ensureActive()
+
                 val folder = BookmarkItem.Folder(
                     guid = guid,
                     title = resolveFolderTitle(rootNode),

mobile/android/fenix/app/src/main/java/org/mozilla/fenix/bookmarks/EditBookmarkFragment.kt

@@ -12,6 +12,7 @@ import androidx.compose.ui.platform.ComposeView
 import androidx.compose.ui.platform.ViewCompositionStrategy
 import androidx.core.content.getSystemService
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavHostController
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
@@ -111,6 +112,7 @@ class EditBookmarkFragment : Fragment(R.layout.fragment_edit_bookmark) {
                                             AppAction.BookmarkAction.BookmarkOperationResultReported(it),
                                         )
                                     },
+                                    lifecycleScope = lifecycleScope,
                                 ),
                             ),
                             bookmarkToLoad = args.guidToEdit,

mobile/android/fenix/app/src/test/java/org/mozilla/fenix/bookmarks/BookmarksMiddlewareTest.kt

@@ -9,7 +9,9 @@ import androidx.navigation.NavBackStackEntry
 import androidx.navigation.NavController
 import androidx.navigation.NavDestination
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
 import kotlinx.coroutines.test.runTest
 import mozilla.appservices.places.BookmarkRoot
@@ -50,6 +52,8 @@ class BookmarksMiddlewareTest {
     @get:Rule
     val coroutineRule = MainCoroutineRule()
 
+    private val testDispatcher = StandardTestDispatcher()
+
     private lateinit var bookmarksStorage: BookmarksStorage
     private lateinit var clipboardManager: ClipboardManager
     private lateinit var addNewTabUseCase: TabsUseCases.AddNewTabUseCase
@@ -2064,6 +2068,7 @@ class BookmarksMiddlewareTest {
         saveBookmarkSortOrder = saveSortOrder,
         lastSavedFolderCache = lastSavedFolderCache,
         reportResultGlobally = reportResultGlobally,
+        lifecycleScope = CoroutineScope(testDispatcher),
     )
 
     private fun BookmarksMiddleware.makeStore(